Safety guard

ABSTRACT

A safety guard for preventing injury to personnel adjacent machinery such as a punch press. A plurality of horizontally extending safety panels are connected at their ends to a pair of lazy tong mechanisms to permit the guard to be swung upwardly to an open position and to be swung downwardly to a closed position to cover the area to be protected.

United States Patent 1191 Mikulin 1 SAFETY GUARD [76] Inventor: Tom T. Mikulin, 1469 Bellevue Ave., Burlingame, Calif. 94010 221 Filed: Mar. 16,1973

21 Appl. No: 342,141

152] US. Cl 74/612, 74/521, 100/53, 248/277 [51] Int. Cl. F16p 1/00 [58] Field of Search 74/612,521; 100/53; 248/277, 280, 324

[56] References Cited UNITED STATES PATENTS 1,496,800 6/1924 Wenander 74/521 2,463,386 3/1949 Hopper 74/521 X 1 June 11, 1974 3,654,821 4/1972 Mikulin 74/612 FOREIGN PATENTS OR APPLICATIONS 650,409 2/1951 Great Britain 74/612 Primary Examiner-Samue1 Scott Assistant Examiner-F. D. Shoemaker [5 7] ABSTRACT A safety guard for preventing injury to personnel adjacent machinery such as a punch press. A plurality of horizontally extending safety panels are connected at their ends to a pair of lazy tong mechanisms to permit the guard to be swung upwardly to an open position and to be swung downwardly to a closed position to cover the area to be protected.

4 Claims, 8 Drawing Figures PATENTEDJUN 1 1 1914 38153140 SHEEI 20F 3 Ma y 66 FIG- 3 SAFETY GUARD This invention relates to safety guards of the type employed to prevent injury to personnel from the operation of machinery. The present invention is similar in some respects to that shown in US. Pat. No. 3,654,821 dated Apr. 1 1, I972 and, in certain respects, is an improvement over the patented guard.

The main object of the present invention is the provision of a safety guard that is effective in achieving the desired purpose and at the same time is less expensive to manufacture than like guards heretofore available. In this connection, the safety guard disclosed in the above noted patent lends itself to high speed operation whether manually or by power means. This is partly due to the fact that the safety panels of the guard are under complete control at all times and move through a vertical path of travel. By contrast, the guard disclosed herein lends itself particularly to manual operation and, although not actuatable at the speed of the patented guard, is nevertheless substantially less expensive to manufacture and is applicable to situations wherein it is not necessary to open the guard very frequently to service the machine.

Other objects and advantages will be apparent from the following specification and from the drawings.

FIG. 1 is a front elevation of the safety guard broken away to reduce the width of ,the view.

FIG. 2 is an end elevation of the guard of FIG. 1 with the guard in closed position and indicating schematically by dot-dash lines the locked position.

FIG. 3 is a view similar to FIG. 2 with the guard shown in partly open position.

FIG. 4 is a view similar to FIG. 2 with the guard shown in fully opened position.

FIG. 5 is an enlarged fragmentary view of the upper end of the guard of FIG. 2.

FIG. 6 is a fragmentary front elevation of the structure of FIG. 5.

FIG. 7 is an enlarged fragmentary view of the lower end of the guard of FIG. 2, showing by dot-dash lines the locked position.

FIG. 8 is a fragmentary front elevation of the structure of FIG. 7.

Referring first to FIG. I, a typical machine such as a punch press 1 is indicated by dotted lines and is provided with a front face 2 to which the safety guard to be described is secured. The guard is shown in closed position in FIG. 1 and essentially comprises a plurality of safety panels adapted to be interposed between the machine and the personnel attending the same. In FIG. 1, upper and lower panels generally designated 3, 4 are provided preferably formed of expanded metal; the central panel 5 may be formed of a tough transparent plastic so as to facilitate viewing the machine therethrough. It will be understood, however, that the particular structure of the panels and the number employed are not critical.

The above noted panels are secured at their opposite ends to corresponding links of a pair of lazy tong mechanisms generally designated 7,8. These mechanisms are substantially identical and only lazy tong mechanism 8 is shown in detail in the remaining views.

Secured to the front 2 of the machine 1 by any convenient means is an angle bar support 10 having an outwardly extending leg 11 at the lower end of which is provided a pivot 12 (FIG. 5). Swingably secured to this pivot is the upper end of an elongated link 13 which in turn is pivotally connected centrally of its length as at 14 to a similar link 15 so that links 13 and 15 form one unit of the lazy tong mechanism 8 (FIG. 2).

Swingably connected to the lower ends of links l3, 15 are a pair of similar links l7, l9 pivoted at pivot 18. Another pair of links 21, 23 are swingably connected at their upper ends to the lower ends of links l7, l9 and, in this case, the lower end of link 21 terminates the pivot 22 whereas the link 23 extends downwardly and is provided at its lower end with a locking mechanism generally designated 24 (FIG. 2). From FIGS. 1, 2 it will be seen that panels 3, 4 and 5 are secured to links 15, 23 and 19 respectively.

The upper end of link 15 is swingably connected to a terminal link 25 which in turn is fixedly secured at its opposite end to a shaft 27 (see FIGS. 5, 6). This shaft 27 is rotatably supported at its opposite ends in the legs 11 of the angle bar supports 10 and is fixedly secured at each end to a gear 28 in mesh with another gear 29 also rotatably supported on leg 11 of angle bar support 10. The angle bar supports 10 may be adequately secured together as a unit by means of upper and lower rods 31, 30 (FIG. 6).

Gear 29 is rotatably supported on a bolt 32 which in turn is fixedly secured to leg 11 by means of nut 33. Also secured to gear 29 is the inner end of an arm 35 which is provided with a counterweight 36 secured to said arm 35 by means of a clamp 37 permitting adjustable movement of the weight 36 along the length of arm 35 to vary the torque imparted to gear 29 by gravity.

.In operation, when the guard is raised from the closed position of FIG. 1 to the completely open position of FIG. 4, it will beapparent that the lower end of the quard swings in an are through an intermediate position indicated in FIG. 3. During such movement it will be apparent from FIG. 5 that arm 35 and counterweight 36 swing downwardly so as to rotate gears 28, 29 in the manner required to create a lifting effort on the guard thereby reducing the amount of force to be exerted by the operator.

At the lower end of the lowermost panel 4 a pair of plates 39 are provided which are connected together by a rod 40. At the outer ends of plates 39, an actuating bar 41 is provided which is fixedly secured to said outer ends of plates 39. This bar is adapted to be grasped by the operator for raising and lowering the guard.

In order to prevent the guard from vibrating to an open position, means is provided for securing the lower end of the guard in closed position to the front face 2 of the machine. Such securement means includes a hub 42 rotatably supported on the end of rod and provided with horizontally outwardly projecting pin 43 which is adapted to be locked under a hook shaped element 44 secured to the front 2 of the machine. To facilitate the locking action a handle 45 is provided on hub 42 so that by swinging the handle 45 upwardly and urging the guard to its innermost position, the handle 45 may then be swung downwardly to cause the pin 43 to engage the hook shaped holder 44. The above described locking mechanism may be duplicated on both sides of the guard as shown in FIG. 1.

Although the above described structure requires sufficient room in front of the machine to permit the guard to be swung outwardly away from this machine in its partially open position as shown in FIG. 3, nevertheless the simplicity of the machine substantially reduces the cost of the same and the guard effectively carries out its purpose. In addition, it will be noted that the amount of effort required to open and close the guard may he reduced considerably by balancing the torque exerted by the weighted arm 35 and the torque exerted by the guard assembly due to gravity.

I claim:

1. A safety guard adapted to be positioned adjacent a machine such as a punch press to protect personnel from injury,- comprising:

a pair of similar horizontally spaced apart parallel lazy tong mechanisms defining the vertically extending sides of said guard,

an upper fixed support,

means securing said mechanisms at their upper ends to said fixed support adjacent said machine, with the opposite lower ends free from engagement,

a plurality of elongated parallel safety panels extending between and secured at their opposite ends to corresponding links of each of said mechanisms,

a pair of terminal links rotatably supported at their corresponding inner ends to said support,

one link of each pair of links of each mechanism adjacent said fixed support being pivotally secured to said support, the other link of each pair adjacent said fixed support being pivoted to the outer end of a terminal link,

the inner end of each of said terminal links being re tatably mounted on said support, counterweight means operatively associated with said other end of said terminal link for applying a torque to said terminal link in the same direction as the direction of movement of said terminal link when said guard is raised. 2. A safety guard according to claim 1 wherein said oneend of said terminal link is fixedly connected to a first gear,

a second gear rotatably mounted on said support and inmesh with said first gear,

a counterweight connected to said second gear to rotate the latter by gravity in a direction opposite to the direction of said terminal link when said guard is raised.

3. A safety guard according to claim 2 wherein a counterweight is provided at each side of said guard and a pair of first and second gears cooperate with each counterweight,

a horizontally extending shaft rotatably supported at its opposite ends in said support and fixedly secured to the innere'nds of said terminal links and to a first gear at each of its ends.

4. A safety'guard according to claim 1 wherein a fixed stop is provided for engaging the lower end of the guard to prevent upward movement of the latter. 

1. A safety guard adapted to be positioned adjacent a machine Such as a punch press to protect personnel from injury, comprising: a pair of similar horizontally spaced apart parallel lazy tong mechanisms defining the vertically extending sides of said guard, an upper fixed support, means securing said mechanisms at their upper ends to said fixed support adjacent said machine, with the opposite lower ends free from engagement, a plurality of elongated parallel safety panels extending between and secured at their opposite ends to corresponding links of each of said mechanisms, a pair of terminal links rotatably supported at their corresponding inner ends to said support, one link of each pair of links of each mechanism adjacent said fixed support being pivotally secured to said support, the other link of each pair adjacent said fixed support being pivoted to the outer end of a terminal link, the inner end of each of said terminal links being rotatably mounted on said support, counterweight means operatively associated with said other end of said terminal link for applying a torque to said terminal link in the same direction as the direction of movement of said terminal link when said guard is raised.
 2. A safety guard according to claim 1 wherein said one end of said terminal link is fixedly connected to a first gear, a second gear rotatably mounted on said support and in mesh with said first gear, a counterweight connected to said second gear to rotate the latter by gravity in a direction opposite to the direction of said terminal link when said guard is raised.
 3. A safety guard according to claim 2 wherein a counterweight is provided at each side of said guard and a pair of first and second gears cooperate with each counterweight, a horizontally extending shaft rotatably supported at its opposite ends in said support and fixedly secured to the inner ends of said terminal links and to a first gear at each of its ends.
 4. A safety guard according to claim 1 wherein a fixed stop is provided for engaging the lower end of the guard to prevent upward movement of the latter. 